318 Over Heating (Its Not Mine!)

So we have this stockish 318 in the 46 truck. One of the smallest comp hydraulic flats (think the 220 cam), 9:1 compression, some blending in the heads with manifolds, Eddy SP-2P intake and 600 holley. Now we have this on going over heating issue that we fix then creeps back.

Symptoms:
In the winter 70* and under the truck does fine.
Once the temp starts to get into the 70-80* range if you pull a hill or turn the A/C on its up in the 200-215* range.
Over 80* you cant run the A/C as its already in the 215* range and will just creep up and up and up.
Cannot bring the timing above 36* (run at 34*)/run vacuum advance or it misfires like crazy, but not ping/knock

What we have done:
Built the truck with the largest possible aluminum radiator, its a 21"x20" (core size) 2 core with a 16lbs cap.
The A/C condenser is mounted 1" off the radiator
Replaced the water pump for a high volume which helped for one week
Greg has a 160* high flow thermostat which again helped for a week
Has a 16" single electric fan with no shroud (no space for another fan or shroud)

Today I pulled the manifold and the intake gaskets are letting a little oil in the ports so they are going to be replaced. Pulled a head and there is a little oil build up in the chambers but not serious, I also checked that the head gasket had holes where it should and it did. Water is traveling thru the block, into the back of the head, then into the manifold in the front.

I think its not enough fan but on the freeway that shouldn't matter, any idea's on whats up?

EDIT: All the front sheet metal is on it.